Work has continued on the use of low dose doxorubicin as a radiation enhancer to improve the effectiveness of I-131 in the treatment of high- risk thyroid cancer. Twenty patients have entered the protocol, 7 of whom were randomized to receive the combination therapy. A total of 19 I-131 treatments combined with adriamycin have been administered with no apparent additional toxicity. A second group of thyroid cancer patients has taken part in a study to test the effectiveness of recombinant human TSH to stimulate uptake in the thyroid remnant following initial thyroidectomy. This Phase I and II study to test efficacy and toxicity is part of a multi-institutional effort in collaboration with Bruce Weintraub and the Genzyme Corporation. The initial results are under evaluation. A third group of thyroid cancer patients are under study to evaluate the use of the serum thyroglubulin (TG) level as a guide to I-131 therapy in patients in whom a diagnostic whole body I-131 scan is negative. Fourteen patients have received up to three treatments with 150 to 300 mCi I-131 and the post therapy scan was positive in 13 patients (in 21 of 28 treatments). Serum TG decreased in 82% of patients, and reverted to less than 5 ug/ml in 29% of patients after one or two treatments. The post therapy whole body scan became negative in 50% of patients after two or three treatments.